Described herein is a “cart system” that allows manipulation of tools (e.g. jackhammer tools) and, more specifically, a wheeled cart system having multiple subsystems (e.g. a lifting subsystem for lifting tools and a tilting subsystem for tilting tools) that relieve the operator from the physical demands of manipulating tools.
Jackhammer tools have been in use for over 150 years for good reason: they are a reasonably-priced, flexible alternative to hand tools for heavy demolition and construction work. In addition to providing a more powerful alternative to sledgehammers and pickaxes, jackhammer tools have led to the development of a family of related tools that are more efficient and less physically demanding than the hand tools they replace. This family of tools includes, for example, diggers, paving breakers, rock drills, tampers and rammers, pick hammers, post-drivers, ground rod drivers, post hole borers, post pullers, and breakers (collectively “jackhammer tool[s]”). While an improvement over hand tools, jackhammer tools exact a heavy price from operators in terms of the physical effort required and physical injuries inflicted. To be effective, jackhammer tools are heavy (typically 60-100 lbs.), extremely loud, and vibrate intensely when in use. As a result, jackhammer tools can be used only by physically fit and strong operators and for limited periods between rest breaks. Over time, operation of jackhammer tools is miserable, exhausting work that is sometimes known as “punishment work” in the trades. In addition, with time, operators experience a variety of injuries that lead to pain, disability, and inability to continue working with these tools. For some potential employees (e.g. most women), the physical demands of these tools function to exclude the potential employees from employment opportunities. For employers, the physical burdens and injuries inflicted by jackhammer tools increase the cost of doing business, lead to employee attrition, and delay work.
A number of technologies have been developed to address the problems and limitations associated with jackhammer tools, and a number of patents have issued for those technologies.
A first group of references disclose lift assist devices that provide mechanical means for lifting jackhammer tools off the ground.                In U.S. Pat. No. 2,622,562 to Longenecker (the “Longenecker reference”), Longenecker discloses a lift assist device consisting of a single acting hydraulic cylinder that, when activated, pushes directly against the working surface to lift the jackhammer tool off of the working surface. In addition to assisting the operator in lifting the heavy tool, the Longenecker device also assists operators in freeing tools that have become jammed in the working surface, a common occurrence with jackhammer tools.        In U.S. Pat. No. 2,776,653 to Eaton (the “Eaton reference”), Eaton discloses a lift assist with dual pneumatic jacks and a semicircular foot designed to better engage with the working surface. It also includes a retraction mechanism for the jacks.        In U.S. Pat. No. 4,548,279 to Zaruba (the “Zaruba reference”), Zaruba discloses a lift assist with a pneumatic jack that remains always in contact with the working surface.        In U.S. Pat. No. 4,986,370 to Johnson et al. (the “Johnson reference”), Johnson et al. disclose a pneumatic lift system that includes a lift plate that remains in contact with the working surface during operation.        In U.S. Pat. No. 6,050,345 to Jarvinen et al. (the “Jarvinen reference”), Jarvinen et al. disclose a lift assist that incorporates a single caster to assist in repositioning of the tool between periods of operation.        In U.S. Pat. No. 7,694,749 to Sorric et al. (the “Sorric reference”), the Sorric brothers disclose a jackhammer tool with integrated lift assist that has dual acting pneumatic cylinders that push against the working surface to lift the tool and retract when not lifting. In one embodiment of the Sorric device, they disclose a pair of small wheels that push against the working surface when lifting, and retract away from the working surface when the tool is operating.        
A second group of references disclose devices that assist in the positioning of jackhammer tools by providing wheeled carts that support all or some of the weight of these jackhammer tools while they are being transported or repositioned.                In U.S. Pat. No. 8,240,682 to Kennard (the “Kennard reference”), Kennard discloses a jackhammer tool trolley that includes a frame with two wheels similar in design to a golf club pull cart. The trolley is designed to assist in transport of jackhammer tools and to permit operation of jackhammer tools while attached to the trolley and held at an angle to the working surface. The trolley supports most of the weight of the jackhammer tool, while held at an angle, assisting operators when using the jackhammer tool to remove floor tiles and similar flooring materials. The trolley does not include a mechanism for mechanical lifting of the jackhammer tool but does include a spring mechanism to provide some assistance in changing the angle of the jackhammer tool in relation to the working surface.        In U.S. Pat. No. 5,462,127 to Svensson (the “Svensson reference”), Svensson discloses another jackhammer tool trolley that incorporates four wheels and shock absorbers designed to reduce the vibration transmitted to the user. The tool is lifted from the working surface by manually tilting the trolley and tool toward the operator.        In U.S. Patent Publication No. 2007/0228805 to Due (the “Due reference”), Due discloses another jackhammer tool trolley that incorporates two driven wheels in a similar arrangement to the device disclosed by Kennard reference.        In PCT Publication No. WO 1989/001892 A1 to Frederick (the “Frederick reference”), Frederick discloses a powered cart with its weight balanced primarily over two powered wheels (but with two additional balance wheels where the skids would be in a wheelbarrow) in an arrangement similar to a two-wheeled wheelbarrow that is designed to carry and provide a power source for a variety of tools and implements, including a wheelbarrow tray, lawnmower, vacuum, chainsaw, concrete saw, or jackhammer tool. The drawings do not show a jackhammer tool, but the description specifies that the jackhammer tool is attached in a fixed position relative to the cart. Therefore, the jackhammer tool is lifted by manually tilting the cart over its main wheels.        In U.S. Patent Publication No. 2013/0098649 to Charbonneau et al. (the “Charbonneau reference”), Charbonneau discloses a support frame for jackhammer tools that includes support structures including wheels and “pods,” a lever for lifting the jackhammer tool by pressing down on handles opposite the jackhammer tool in a teeter-totter arrangement, and a “joystick” for moving the jackhammer tool from side to side while lifting.        